Sample transport tubes: UN3373, temperature, and time – lab checklist
Transport of Category B biological material labeled UN3373 is subject to strictly defined regulatory requirements. Failure to meet these requirements may result in the sample being rejected by the receiving laboratory or in legal consequences for the sender. Selecting the appropriate tube is a necessary but not sufficient condition, as temperature control throughout the entire transport process and adherence to allowable time windows are equally important. The checklist below organizes these requirements into a practical format for daily laboratory work.
How to select tubes for transport in compliance with UN3373 requirements?
The UN3373 regulation applies to the transport of Category B biological substances and defines requirements for primary, secondary, and outer packaging, which together form a triple packaging system. The primary container, i.e., the tube in direct contact with the sample, must be leak-proof, resistant to leakage, and made of material approved for contact with biological substances. The tightness of the connection between the tube and its closure is the most common source of non-compliance detected during audits. The outer packaging must be permanently labeled with the UN3373 mark along with the UN number and proper shipping name.
Key features of tubes for transporting biological material
A tube intended for transport under the UN3373 system should meet several conditions simultaneously, which together determine the safety and integrity of the sample. The tightness of the screw cap is a critical parameter, as push caps and rubber stoppers do not guarantee sufficient sealing under pressure changes during air or road transport. Tubes offered by Noex Labware are made of high-quality plastics with screw caps ensuring maximum tightness and are available in aseptic and sterile versions suitable for biological material transport.
Required features of a tube for UN3373 transport include:
- leak-proof screw closure resistant to pressure changes and vibrations,
- material approved for contact with biological substances, not releasing compounds that could interfere with analysis,
- mechanical resistance to impact and compression within the secondary packaging,
- transparency allowing visual inspection of contents without opening the tube,
- documentation confirming compliance with regulatory requirements.
Importance of temperature and time control during sample transport
The stability of a biological sample during transport depends primarily on the duration of exposure to improper temperatures, as most analytes degrade exponentially when exposed to temperatures above recommended levels. Any deviation from the required temperature range shortens the effective time window for a given sample type and may lead to false results without any visible physicochemical changes. Continuous temperature monitoring throughout transport provides evidence in case of disputes regarding result reliability and should be a standard for every diagnostic shipment.
Methods for maintaining stable conditions for samples
The choice of cooling method should depend on the required temperature range and transport duration, as different cooling media provide different temperature profiles. Gel packs preconditioned to +4°C are suitable for samples requiring cooling without freezing, while dry ice should be used only for samples approved for subzero temperatures, as improper use may irreversibly damage biological material. Temperature data loggers placed in the secondary packaging enable verification of conditions upon delivery and should be a standard component of every shipment.
Checklist: safe transport of laboratory samples
The following checklist covers key verification points before shipment and after receipt of samples transported under the UN3373 system.
Before shipment – tube and packaging:
- tube with a screw cap, tightly closed and visually inspected for cracks,
- tube placed in secondary packaging with absorbent material capable of absorbing at least the sample volume,
- outer packaging labeled with the UN3373 mark, UN number, and proper shipping name,
- accompanying documentation compliant with carrier and national regulatory requirements.
Before shipment – temperature and time:
- cooling medium selected according to the required temperature range of the sample,
- temperature data logger placed in the secondary packaging, activated and calibrated,
- estimated transport time not exceeding the allowable time window for the sample type,
- sample collected no earlier than permitted by analyte stability under intended conditions.
After receipt:
- verification of temperature records from the data logger,
- visual inspection of tube tightness and packaging condition,
- recording of the time from collection to receipt in the sample documentation,
- rejection of the sample and notification of the sender in case of temperature excursions or packaging damage.
Noex Labware Sp. z o.o., located at Fabianowska 119–121 in Komorniki near Poznań, has been manufacturing laboratory tubes and swabs for over 40 years. Contact: +48 61 810 88 15.
Summary
- A tube for UN3373 transport must have a leak-proof screw cap, be mechanically resistant, and be made of material approved for contact with biological substances.
- Exceeding the temperature range shortens the effective sample time window and may lead to false results without visible physicochemical changes.
- Gel packs at +4°C are used for samples requiring cooling without freezing, while dry ice is used exclusively for samples approved for subzero temperatures.
- Temperature data loggers should be a standard component of every diagnostic shipment as proof of maintaining conditions throughout transport.
- A verification checklist before shipment and after receipt minimizes the risk of rejection and ensures the reliability of analytical results.
FAQ
What tubes meet UN3373 requirements for sample transport?
Tubes compliant with UN3373 must be leak-proof, resistant to damage, and appropriately labeled. They must be made of materials approved for contact with biological material and have certification confirming compliance with relevant standards.
How to control temperature during sample transport?
Temperature control is achieved using insulated packaging, cooling packs, and temperature data loggers. Maintaining proper conditions minimizes sample degradation and ensures reliable results.
How long can samples be transported in tubes without loss of quality?
Transport time depends on the sample type and storage conditions but typically should not exceed a few hours up to a maximum of 24 hours. For longer transport, maintaining proper temperature is critical.
Can any tube be used for transporting infectious material?
No, only tubes that meet specific safety standards, including UN3373, should be used for transporting infectious materials. Standard tubes may not ensure sufficient tightness or resistance to external factors.